1. Field of the Invention
The present invention relates to a titanyl phthalocyanin crystal prepared from a titanyl phthalocyanin compound, the method for preparing the same and an electrophotographic photoconductor using the same. Particularly, the present invention relates to a titanyl phthalocyanin crystal excellent in the storage stability in organic solvents, the method for preparing the same and an electrophotographic photoconductor using the same.
2. Related Art
Generally, organic photoconductors have been frequently and recently used in electrophotographic photoconductors applied in electrophotographic devices such as a copy machine and a laser printer, etc. upon such requirements as low cost and low environment polluting property, etc. Phthalocyanin pigments that are sensitive to a light of infrared to near-infrared wavelengths irradiated from a semiconductor laser or an infrared LED, etc. have been widely used as charge-generating agent used in such organic photoconductors.
It has been known that metal-free phthalocyanin compounds, copper phthalocyanin compounds, titanyl phthalocyanin compounds, etc. exist in such phthalocyanin pigments depending on a chemical structure thereof, and various crystal types can be obtained due to different preparation conditions for each phthalocyanin compound.
Thus, it has been known that when a photoconductor using a titanyl phthalocyanin with a Y-type crystal structure as a charge-generating agent is constituted in the existence of many types of phthalocyanin compound crystals having different crystal types, electric characteristics in the photoconductor is improved as compared with a case of using tithanylphthalocyanines of other crystal types.
For example, there has been disclosed a method for preparing a Y-type crystal prepared by reacting a titanium compound and an organic compound that is a titanyl phthalocyanin having the maximum peak at a Bragg angle (2 θ±0.2°)=27.3° for a CuKα line in an X-ray diffraction spectrum and can form a phthalocyanin ring under conditions of 130° C. and about 4 hrs in dialkyl-aminoalcohol added with urea or ammonia (e.g., Patent document 1).
There has also been disclosed a method for preparing a titanium phthalocyanin compound of Y-type crystal prepared by directly reacting o-phthalonitrile and titanium tetrabutoxide without using a urea compound under conditions of 215° C. and about 2 hrs (e.g., Patent documents 2 and 3).
More specifically, there has been disclosed a method for preparing a titanyl phthalocyanin crystal having a peak within a predetermined range in the CuKα characteristic X-ray diffraction spectrum and no peak within the range of 50 to 400° C. in the differential scanning calorimetric analysis.
[Patent document 1] JPH8-176456A (examples)
[Patent document 2] JP2001-181531 (claims)
[Patent document 3] JP2004-145284A (claims)